1. Field of the Invention
The present invention relates to paper clips and more particularly pertains to a spring-biased paper clip having improved opening means and paper gripping surfaces.
2. Description of the Prior Art
The use of various types of spring clips for holding sheets of paper together are well known in the prior art. For example, a representative embodiment of a spring clip formed from a single sheet of elastic metal plate is to be found in U.S. Pat. No. 5,309,605, which issued to Sato on May 10, 1994. Another example of this type of integral clip is to be found in U.S. Pat. No. 4,947,524, which issued to Chang on Aug. 14, 1990, wherein there is disclosed a paper clip formed from a single sheet of steel that has been bent into a U-shaped structure.
In addition to paper clips formed from a single sheet of material, there has been an effort to develop paper clips formed from a plurality of parts. An example of this type of multi-part paper clip is shown in U.S. Pat. No. 5,079,808, which issued to Brown on Jan. 14, 1992. The Brown Patent discloses a paper clip formed from a pair of plate elements having clamping edges and being hingedly connected together. A cantilever spring extends from an inner surface of one plate element and engages the inner surface of the opposite plate element, and the cantilever spring is utilized to provide an increasing clamping force with increasing document thickness. A plurality of ridges are provided on the clamping edges of the plates, and the ridges are designed to be parallely aligned and overlapping so as to achieve a better grip on documents retained between the plates.
While each of these prior art patents disclose paper gripping devices which fulfill their respective particular objectives and requirements, and are most likely quite functional for their intended purposes, it will be noted that none of the illustrated paper clips are particularly designed for holding large quantities of paper together through the use of specialized gripping surfaces, increased spring strength, and improved means for forcing paper engaging surfaces apart as would be necessary when utilizing a high tension spring. In this respect, the present invention substantially fulfills this need.